|VCS Wi-Fi Configuration Best Practices / WLAN Settings|
Depending on location, some channels may not be available in the 5GHz frequency band. Channel use is limited by each country's regulatory agency.
Some of the 5 GHz channels are sometimes not available, as other applications (primarily RADAR) have priority use. If the Wi-Fi is using one of these channels and the AP detects it is being used by RADAR, the AP will change channels. When this happens, the clients associated with that AP will be forced to look for another AP. If a voice call is active during the channel change, voice audio will be interrupted.
If your facility is near an airport or a weather station (common users of RADAR), you should disable DFS channels.